Bird cage



FIG. 1 is a perspective view of a bird cage showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a right side elevational view thereof; and

FIG. 5 is a top plan view thereof. 

The ornamental design for a bird cage, as shown and described. 